drivers/acpi/hardware/hwacpi.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2006, R. Byron Moore
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #include <acpi/acpi.h>
  46
  47 #define _COMPONENT          ACPI_HARDWARE
  48 ACPI_MODULE_NAME("hwacpi")
  49
  50 /******************************************************************************
  51  *
  52  * FUNCTION:    acpi_hw_initialize
  53  *
  54  * PARAMETERS:  None
  55  *
  56  * RETURN:      Status
  57  *
  58  * DESCRIPTION: Initialize and validate the various ACPI registers defined in
  59  *              the FADT.
  60  *
  61  ******************************************************************************/
  62 acpi_status acpi_hw_initialize(void)
  63 {
  64         acpi_status status;
  65
  66         ACPI_FUNCTION_TRACE(hw_initialize);
  67
  68         /* We must have the ACPI tables by the time we get here */
  69
  70         if (!acpi_gbl_FADT) {
  71                 ACPI_ERROR((AE_INFO, "No FADT is present"));
  72                 return_ACPI_STATUS(AE_NO_ACPI_TABLES);
  73         }
  74
  75         /* Sanity check the FADT for valid values */
  76
  77         status = acpi_ut_validate_fadt();
  78         if (ACPI_FAILURE(status)) {
  79                 return_ACPI_STATUS(status);
  80         }
  81
  82         return_ACPI_STATUS(AE_OK);
  83 }
  84
  85 /******************************************************************************
  86  *
  87  * FUNCTION:    acpi_hw_set_mode
  88  *
  89  * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
  90  *
  91  * RETURN:      Status
  92  *
  93  * DESCRIPTION: Transitions the system into the requested mode.
  94  *
  95  ******************************************************************************/
  96
  97 acpi_status acpi_hw_set_mode(u32 mode)
  98 {
  99
 100         acpi_status status;
 101         u32 retry;
 102
 103         ACPI_FUNCTION_TRACE(hw_set_mode);
 104
 105         /*
 106          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 107          * system does not support mode transition.
 108          */
 109         if (!acpi_gbl_FADT->smi_cmd) {
 110                 ACPI_ERROR((AE_INFO,
 111                             "No SMI_CMD in FADT, mode transition failed"));
 112                 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 113         }
 114
 115         /*
 116          * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
 117          * in FADT: If it is zero, enabling or disabling is not supported.
 118          * As old systems may have used zero for mode transition,
 119          * we make sure both the numbers are zero to determine these
 120          * transitions are not supported.
 121          */
 122         if (!acpi_gbl_FADT->acpi_enable && !acpi_gbl_FADT->acpi_disable) {
 123                 ACPI_ERROR((AE_INFO,
 124                             "No ACPI mode transition supported in this system (enable/disable both zero)"));
 125                 return_ACPI_STATUS(AE_OK);
 126         }
 127
 128         switch (mode) {
 129         case ACPI_SYS_MODE_ACPI:
 130
 131                 /* BIOS should have disabled ALL fixed and GP events */
 132
 133                 status = acpi_os_write_port(acpi_gbl_FADT->smi_cmd,
 134                                             (u32) acpi_gbl_FADT->acpi_enable,
 135                                             8);
 136                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 137                                   "Attempting to enable ACPI mode\n"));
 138                 break;
 139
 140         case ACPI_SYS_MODE_LEGACY:
 141
 142                 /*
 143                  * BIOS should clear all fixed status bits and restore fixed event
 144                  * enable bits to default
 145                  */
 146                 status = acpi_os_write_port(acpi_gbl_FADT->smi_cmd,
 147                                             (u32) acpi_gbl_FADT->acpi_disable,
 148                                             8);
 149                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 150                                   "Attempting to enable Legacy (non-ACPI) mode\n"));
 151                 break;
 152
 153         default:
 154                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 155         }
 156
 157         if (ACPI_FAILURE(status)) {
 158                 ACPI_EXCEPTION((AE_INFO, status,
 159                                 "Could not write ACPI mode change"));
 160                 return_ACPI_STATUS(status);
 161         }
 162
 163         /*
 164          * Some hardware takes a LONG time to switch modes. Give them 3 sec to
 165          * do so, but allow faster systems to proceed more quickly.
 166          */
 167         retry = 3000;
 168         while (retry) {
 169                 if (acpi_hw_get_mode() == mode) {
 170                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 171                                           "Mode %X successfully enabled\n",
 172                                           mode));
 173                         return_ACPI_STATUS(AE_OK);
 174                 }
 175                 acpi_os_stall(1000);
 176                 retry--;
 177         }
 178
 179         ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
 180         return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 181 }
 182
 183 /*******************************************************************************
 184  *
 185  * FUNCTION:    acpi_hw_get_mode
 186  *
 187  * PARAMETERS:  none
 188  *
 189  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 190  *
 191  * DESCRIPTION: Return current operating state of system.  Determined by
 192  *              querying the SCI_EN bit.
 193  *
 194  ******************************************************************************/
 195
 196 u32 acpi_hw_get_mode(void)
 197 {
 198         acpi_status status;
 199         u32 value;
 200
 201         ACPI_FUNCTION_TRACE(hw_get_mode);
 202
 203         /*
 204          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 205          * system does not support mode transition.
 206          */
 207         if (!acpi_gbl_FADT->smi_cmd) {
 208                 return_UINT32(ACPI_SYS_MODE_ACPI);
 209         }
 210
 211         status =
 212             acpi_get_register(ACPI_BITREG_SCI_ENABLE, &value, ACPI_MTX_LOCK);
 213         if (ACPI_FAILURE(status)) {
 214                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 215         }
 216
 217         if (value) {
 218                 return_UINT32(ACPI_SYS_MODE_ACPI);
 219         } else {
 220                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 221         }
 222 }